Induced mutations in interspecific hybrids of abolmochus

Abstract

The F1 seeds of the cross between Abelmoschus esculentus cv Kiran and the semi- wild species, Abelmoschus manihot were exposed to four different doses (10, 20, 30 and 40 KR) of gama rays and their effects in the first generation were studied. The percentage of seed germination decreased with increasing doses of gamma rays. The treated hybrids have shown delyed germination compared to the control. The survival of plants was found to decrease with increase in dose of the mutagen. The rate of growth of plants and plant height were found to decrease by the treatment with gamma rays. Various chlorophyll and morphological varients were observed in the irradiated population. An increase in pollen fertility was noticed in the irradiated hybrids. But the increased pollen fertility did not show any effect on the seed set. Irradiation delayed the formation of flowers and fruiting. The mean values for number and weight of fruits did not differ significantly among irradiated treatments and was on par with the control F1. The treated hybrids were found to be on par with the control F1 for yellow vein mosaic disease incidence and the important diseases affecting bhindi. The hybrids irradiated at higher doses had become more susceptiable to fruit borer incidence. The hybrids represented more towards the semi-wild parent and have shown considerable heterosis over the cultivated parent and semi-wild parent for most of the economic characters. The hybrids were vigorous in growth habit compared to the parents. The hybrid treatments exhibited significant positive heterosis for days taken to first flowering and last fruiting over the cultivated parent. The hybrids treatments exhibited significant positive heterosis for number of flowers, number of fruits and weight of fruits over both the parents. Significant negative heterosis over the cultivated parent was shown for fruit length by the hybrid treatments. Significant negative heterosis over the cultivated parent for fruit borer incidence was shown by the control and the hybrids irradiated at 10 and 20 KR. All the hybrid treatments manifested significant negative heterosis over the cultivated parent for YVMD incidence. The mutagenic effectiveness in inducing chlorophyll mutations was found to increase with increase in dose of the gamma rays. The mutagenic efficiency estmated on the basis of lethality and injury increased with increase in dose of gamma rays. On sterility basis, the 30 KR treatments was the most efficient.